diff --git a/mozilla/htmlparser/src/nsExpatTokenizer.cpp b/mozilla/htmlparser/src/nsExpatTokenizer.cpp
index 973c98d87f4..bf303f40da8 100644
--- a/mozilla/htmlparser/src/nsExpatTokenizer.cpp
+++ b/mozilla/htmlparser/src/nsExpatTokenizer.cpp
@@ -30,6 +30,7 @@
 // #include "nsParser.h"
 #include "nsIParser.h"
 #include "prlog.h"
+#include <string.h>
 
 
  /************************************************************************
@@ -154,22 +155,69 @@ nsExpatTokenizer::~nsExpatTokenizer(){
   Here begins the real working methods for the tokenizer.
  *******************************************************************/
 
-/* Called immediately after an error has occurred in expat.  Creates
-   an error token and pushes it onto the token queue.
-*/
-void nsExpatTokenizer::PushXMLErrorToken(void)
+
+static void SetErrorContextInfo(nsParserError* aError, PRUint32 aByteIndex, 
+                                const char* aSourceBuffer, PRUint32 aLength)
+{
+  /* Figure out the substring inside aSourceBuffer that contains the line on which the error
+     occurred.  Copy the line into error->sourceLine */
+  PR_ASSERT(aByteIndex > 0 && aByteIndex < aLength);
+  char* start = (char* ) &aSourceBuffer[aByteIndex];  /* Will try to find the start of the line */
+  char* end = (char* ) &aSourceBuffer[aByteIndex];    /* Will try to find the end of the line */
+  PRUint32 startIndex = aByteIndex;          /* Track the position of the 'start' pointer into the buffer */
+  PRUint32 endIndex = aByteIndex;          /* Track the position of the 'end' pointer into the buffer */
+  PRBool reachedStart;
+  PRBool reachedEnd;
+
+  /* Use start to find the first new line before the error position and
+     end to find the first new line after the error position */
+  reachedStart = ('\n' == *start || '\r' == *start || startIndex <= 0);
+  reachedEnd = ('\n' == *end || '\r' == *end || endIndex >= aLength);
+  while (!reachedStart || !reachedEnd) {
+    if (!reachedStart) {
+      start--;
+      startIndex--;
+    }
+    if (!reachedEnd) {
+      end++;
+      endIndex++;
+    }
+    reachedStart = ('\n' == *start || '\r' == *start || startIndex <= 0);
+    reachedEnd = ('\n' == *end || '\r' == *end || endIndex >= aLength);
+  }
+
+  if (startIndex == endIndex) {
+    /* Special case if the error is on a line where the only character is a newline */
+    aError->sourceLine.Append("");
+  }
+  else {
+    PR_ASSERT(endIndex - startIndex >= 2);
+    
+    /* At this point, the substring starting at (startIndex + 1) and ending at (endIndex - 1),
+       is the line on which the error occurred. Copy that substring into the error structure. */
+    char* tempLine = new char[endIndex - startIndex];
+    strncpy(tempLine, &aSourceBuffer[startIndex + 1], (endIndex - 1) - startIndex);
+    tempLine[endIndex - startIndex - 1] = '\0';
+    aError->sourceLine.Append(tempLine);
+    delete [] tempLine;
+  }
+}
+
+/* 
+ * Called immediately after an error has occurred in expat.  Creates
+ * an error token and pushes it onto the token queue.
+ *
+ */
+void nsExpatTokenizer::PushXMLErrorToken(const char *aBuffer, PRUint32 aLength)
 {
   CErrorToken* token= (CErrorToken *) gTokenRecycler->CreateTokenOfType(eToken_error, eHTMLTag_unknown);
   nsParserError *error = new nsParserError;
   
   error->code = XML_GetErrorCode(mExpatParser);
   error->lineNumber = XML_GetCurrentLineNumber(mExpatParser);
-  error->colNumber = XML_GetCurrentColumnNumber(mExpatParser);
-  // XXX Does the copy constructor of nsString free the passed in char *?
-  error->description = XML_ErrorString(error->code);
-  // XXX Not setting a source buffer and error offset for now
-  error->offset = 0;
-  error->sourceBuffer = "";
+  error->colNumber = XML_GetCurrentColumnNumber(mExpatParser);  
+  error->description = XML_ErrorString(error->code);  
+  SetErrorContextInfo(error, (PRUint32) XML_GetCurrentByteIndex(mExpatParser), aBuffer, aLength);  
 
   token->SetError(error);
 
@@ -182,7 +230,7 @@ nsresult nsExpatTokenizer::ParseXMLBuffer(const char *aBuffer, PRUint32 aLength)
   if (mExpatParser) {
     PR_ASSERT(aLength == strlen(aBuffer));
     if (!XML_Parse(mExpatParser, aBuffer, aLength, PR_FALSE)) {      
-      PushXMLErrorToken();      
+      PushXMLErrorToken(aBuffer, aLength);      
     }
   }
   else {
diff --git a/mozilla/htmlparser/src/nsExpatTokenizer.h b/mozilla/htmlparser/src/nsExpatTokenizer.h
index 428b6026468..e9d8d67b8a3 100644
--- a/mozilla/htmlparser/src/nsExpatTokenizer.h
+++ b/mozilla/htmlparser/src/nsExpatTokenizer.h
@@ -70,7 +70,7 @@ protected:
      */
     void SetupExpatCallbacks(void);
 
-    void PushXMLErrorToken(void);
+    void PushXMLErrorToken(const char *aBuffer, PRUint32 aLength);
 
     /* The callback handlers that get called from the expat parser */
     static void HandleStartElement(void *userData, const XML_Char *name, const XML_Char **atts);
diff --git a/mozilla/htmlparser/src/nsHTMLTags.cpp b/mozilla/htmlparser/src/nsHTMLTags.cpp
index bfb9ab3b219..504bbe0ca53 100644
--- a/mozilla/htmlparser/src/nsHTMLTags.cpp
+++ b/mozilla/htmlparser/src/nsHTMLTags.cpp
@@ -31,10 +31,10 @@ static char* tagTable[] = {
   "kbd", "keygen", "label", "layer", "legend", "li", "link", "listing", 
   "map", "menu", "meta", "multicol", "nobr", "noembed", "noframes", 
   "nolayer", "noscript", "object", "ol", "optgroup", "option", "p", "param", 
-  "plaintext", "pre", "q", "s", "samp", "script", "select", "server", 
-  "small", "sound", "spacer", "span", "strike", "strong", "style", "sub", 
-  "sup", "table", "tbody", "td", "textarea", "tfoot", "th", "thead", "title", 
-  "tr", "tt", "u", "ul", "var", "wbr", "xmp"
+  "parsererror", "plaintext", "pre", "q", "s", "samp", "script", "select", 
+  "server", "small", "sound", "sourcetext", "spacer", "span", "strike", 
+  "strong", "style", "sub", "sup", "table", "tbody", "td", "textarea", 
+  "tfoot", "th", "thead", "title", "tr", "tt", "u", "ul", "var", "wbr", "xmp"
 };
 
 nsHTMLTag NS_TagToEnum(const char* aTagName) {
diff --git a/mozilla/htmlparser/src/nsHTMLTags.h b/mozilla/htmlparser/src/nsHTMLTags.h
index a2209558c97..6e5e4195b44 100644
--- a/mozilla/htmlparser/src/nsHTMLTags.h
+++ b/mozilla/htmlparser/src/nsHTMLTags.h
@@ -46,24 +46,25 @@ enum nsHTMLTag {
   eHTMLTag_nobr=66, eHTMLTag_noembed=67, eHTMLTag_noframes=68, 
   eHTMLTag_nolayer=69, eHTMLTag_noscript=70, eHTMLTag_object=71, 
   eHTMLTag_ol=72, eHTMLTag_optgroup=73, eHTMLTag_option=74, eHTMLTag_p=75, 
-  eHTMLTag_param=76, eHTMLTag_plaintext=77, eHTMLTag_pre=78, eHTMLTag_q=79, 
-  eHTMLTag_s=80, eHTMLTag_samp=81, eHTMLTag_script=82, eHTMLTag_select=83, 
-  eHTMLTag_server=84, eHTMLTag_small=85, eHTMLTag_sound=86, 
-  eHTMLTag_spacer=87, eHTMLTag_span=88, eHTMLTag_strike=89, 
-  eHTMLTag_strong=90, eHTMLTag_style=91, eHTMLTag_sub=92, eHTMLTag_sup=93, 
-  eHTMLTag_table=94, eHTMLTag_tbody=95, eHTMLTag_td=96, eHTMLTag_textarea=97, 
-  eHTMLTag_tfoot=98, eHTMLTag_th=99, eHTMLTag_thead=100, eHTMLTag_title=101, 
-  eHTMLTag_tr=102, eHTMLTag_tt=103, eHTMLTag_u=104, eHTMLTag_ul=105, 
-  eHTMLTag_var=106, eHTMLTag_wbr=107, eHTMLTag_xmp=108, 
+  eHTMLTag_param=76, eHTMLTag_parsererror=77, eHTMLTag_plaintext=78, 
+  eHTMLTag_pre=79, eHTMLTag_q=80, eHTMLTag_s=81, eHTMLTag_samp=82, 
+  eHTMLTag_script=83, eHTMLTag_select=84, eHTMLTag_server=85, 
+  eHTMLTag_small=86, eHTMLTag_sound=87, eHTMLTag_sourcetext=88, 
+  eHTMLTag_spacer=89, eHTMLTag_span=90, eHTMLTag_strike=91, 
+  eHTMLTag_strong=92, eHTMLTag_style=93, eHTMLTag_sub=94, eHTMLTag_sup=95, 
+  eHTMLTag_table=96, eHTMLTag_tbody=97, eHTMLTag_td=98, eHTMLTag_textarea=99, 
+  eHTMLTag_tfoot=100, eHTMLTag_th=101, eHTMLTag_thead=102, 
+  eHTMLTag_title=103, eHTMLTag_tr=104, eHTMLTag_tt=105, eHTMLTag_u=106, 
+  eHTMLTag_ul=107, eHTMLTag_var=108, eHTMLTag_wbr=109, eHTMLTag_xmp=110, 
 
   /* The remaining enums are not for tags */
-  eHTMLTag_text=109, eHTMLTag_whitespace=110, eHTMLTag_newline=111, 
-  eHTMLTag_comment=112, eHTMLTag_entity=113, eHTMLTag_userdefined=114, 
-  eHTMLTag_secret_h1style=115, eHTMLTag_secret_h2style=116, 
-  eHTMLTag_secret_h3style=117, eHTMLTag_secret_h4style=118, 
-  eHTMLTag_secret_h5style=119, eHTMLTag_secret_h6style=120
+  eHTMLTag_text=111, eHTMLTag_whitespace=112, eHTMLTag_newline=113, 
+  eHTMLTag_comment=114, eHTMLTag_entity=115, eHTMLTag_userdefined=116, 
+  eHTMLTag_secret_h1style=117, eHTMLTag_secret_h2style=118, 
+  eHTMLTag_secret_h3style=119, eHTMLTag_secret_h4style=120, 
+  eHTMLTag_secret_h5style=121, eHTMLTag_secret_h6style=122
 };
-#define NS_HTML_TAG_MAX 108
+#define NS_HTML_TAG_MAX 110
 
 extern NS_HTMLPARS nsHTMLTag NS_TagToEnum(const char* aTag);
 extern NS_HTMLPARS const char* NS_EnumToTag(nsHTMLTag aEnum);
diff --git a/mozilla/htmlparser/src/nsParserError.h b/mozilla/htmlparser/src/nsParserError.h
index f2cab09e790..7925f0dd623 100644
--- a/mozilla/htmlparser/src/nsParserError.h
+++ b/mozilla/htmlparser/src/nsParserError.h
@@ -35,9 +35,8 @@ typedef struct _nsParserError {
   PRInt32 code;
   PRInt32 lineNumber;
   PRInt32 colNumber;  
-  nsString description;
-  PRInt32 offset;  
-  nsString sourceBuffer;
+  nsString description;  
+  nsString sourceLine;
 } nsParserError;
 
 #endif
diff --git a/mozilla/parser/htmlparser/src/nsExpatTokenizer.cpp b/mozilla/parser/htmlparser/src/nsExpatTokenizer.cpp
index 973c98d87f4..bf303f40da8 100644
--- a/mozilla/parser/htmlparser/src/nsExpatTokenizer.cpp
+++ b/mozilla/parser/htmlparser/src/nsExpatTokenizer.cpp
@@ -30,6 +30,7 @@
 // #include "nsParser.h"
 #include "nsIParser.h"
 #include "prlog.h"
+#include <string.h>
 
 
  /************************************************************************
@@ -154,22 +155,69 @@ nsExpatTokenizer::~nsExpatTokenizer(){
   Here begins the real working methods for the tokenizer.
  *******************************************************************/
 
-/* Called immediately after an error has occurred in expat.  Creates
-   an error token and pushes it onto the token queue.
-*/
-void nsExpatTokenizer::PushXMLErrorToken(void)
+
+static void SetErrorContextInfo(nsParserError* aError, PRUint32 aByteIndex, 
+                                const char* aSourceBuffer, PRUint32 aLength)
+{
+  /* Figure out the substring inside aSourceBuffer that contains the line on which the error
+     occurred.  Copy the line into error->sourceLine */
+  PR_ASSERT(aByteIndex > 0 && aByteIndex < aLength);
+  char* start = (char* ) &aSourceBuffer[aByteIndex];  /* Will try to find the start of the line */
+  char* end = (char* ) &aSourceBuffer[aByteIndex];    /* Will try to find the end of the line */
+  PRUint32 startIndex = aByteIndex;          /* Track the position of the 'start' pointer into the buffer */
+  PRUint32 endIndex = aByteIndex;          /* Track the position of the 'end' pointer into the buffer */
+  PRBool reachedStart;
+  PRBool reachedEnd;
+
+  /* Use start to find the first new line before the error position and
+     end to find the first new line after the error position */
+  reachedStart = ('\n' == *start || '\r' == *start || startIndex <= 0);
+  reachedEnd = ('\n' == *end || '\r' == *end || endIndex >= aLength);
+  while (!reachedStart || !reachedEnd) {
+    if (!reachedStart) {
+      start--;
+      startIndex--;
+    }
+    if (!reachedEnd) {
+      end++;
+      endIndex++;
+    }
+    reachedStart = ('\n' == *start || '\r' == *start || startIndex <= 0);
+    reachedEnd = ('\n' == *end || '\r' == *end || endIndex >= aLength);
+  }
+
+  if (startIndex == endIndex) {
+    /* Special case if the error is on a line where the only character is a newline */
+    aError->sourceLine.Append("");
+  }
+  else {
+    PR_ASSERT(endIndex - startIndex >= 2);
+    
+    /* At this point, the substring starting at (startIndex + 1) and ending at (endIndex - 1),
+       is the line on which the error occurred. Copy that substring into the error structure. */
+    char* tempLine = new char[endIndex - startIndex];
+    strncpy(tempLine, &aSourceBuffer[startIndex + 1], (endIndex - 1) - startIndex);
+    tempLine[endIndex - startIndex - 1] = '\0';
+    aError->sourceLine.Append(tempLine);
+    delete [] tempLine;
+  }
+}
+
+/* 
+ * Called immediately after an error has occurred in expat.  Creates
+ * an error token and pushes it onto the token queue.
+ *
+ */
+void nsExpatTokenizer::PushXMLErrorToken(const char *aBuffer, PRUint32 aLength)
 {
   CErrorToken* token= (CErrorToken *) gTokenRecycler->CreateTokenOfType(eToken_error, eHTMLTag_unknown);
   nsParserError *error = new nsParserError;
   
   error->code = XML_GetErrorCode(mExpatParser);
   error->lineNumber = XML_GetCurrentLineNumber(mExpatParser);
-  error->colNumber = XML_GetCurrentColumnNumber(mExpatParser);
-  // XXX Does the copy constructor of nsString free the passed in char *?
-  error->description = XML_ErrorString(error->code);
-  // XXX Not setting a source buffer and error offset for now
-  error->offset = 0;
-  error->sourceBuffer = "";
+  error->colNumber = XML_GetCurrentColumnNumber(mExpatParser);  
+  error->description = XML_ErrorString(error->code);  
+  SetErrorContextInfo(error, (PRUint32) XML_GetCurrentByteIndex(mExpatParser), aBuffer, aLength);  
 
   token->SetError(error);
 
@@ -182,7 +230,7 @@ nsresult nsExpatTokenizer::ParseXMLBuffer(const char *aBuffer, PRUint32 aLength)
   if (mExpatParser) {
     PR_ASSERT(aLength == strlen(aBuffer));
     if (!XML_Parse(mExpatParser, aBuffer, aLength, PR_FALSE)) {      
-      PushXMLErrorToken();      
+      PushXMLErrorToken(aBuffer, aLength);      
     }
   }
   else {
diff --git a/mozilla/parser/htmlparser/src/nsExpatTokenizer.h b/mozilla/parser/htmlparser/src/nsExpatTokenizer.h
index 428b6026468..e9d8d67b8a3 100644
--- a/mozilla/parser/htmlparser/src/nsExpatTokenizer.h
+++ b/mozilla/parser/htmlparser/src/nsExpatTokenizer.h
@@ -70,7 +70,7 @@ protected:
      */
     void SetupExpatCallbacks(void);
 
-    void PushXMLErrorToken(void);
+    void PushXMLErrorToken(const char *aBuffer, PRUint32 aLength);
 
     /* The callback handlers that get called from the expat parser */
     static void HandleStartElement(void *userData, const XML_Char *name, const XML_Char **atts);
diff --git a/mozilla/parser/htmlparser/src/nsHTMLTags.cpp b/mozilla/parser/htmlparser/src/nsHTMLTags.cpp
index bfb9ab3b219..504bbe0ca53 100644
--- a/mozilla/parser/htmlparser/src/nsHTMLTags.cpp
+++ b/mozilla/parser/htmlparser/src/nsHTMLTags.cpp
@@ -31,10 +31,10 @@ static char* tagTable[] = {
   "kbd", "keygen", "label", "layer", "legend", "li", "link", "listing", 
   "map", "menu", "meta", "multicol", "nobr", "noembed", "noframes", 
   "nolayer", "noscript", "object", "ol", "optgroup", "option", "p", "param", 
-  "plaintext", "pre", "q", "s", "samp", "script", "select", "server", 
-  "small", "sound", "spacer", "span", "strike", "strong", "style", "sub", 
-  "sup", "table", "tbody", "td", "textarea", "tfoot", "th", "thead", "title", 
-  "tr", "tt", "u", "ul", "var", "wbr", "xmp"
+  "parsererror", "plaintext", "pre", "q", "s", "samp", "script", "select", 
+  "server", "small", "sound", "sourcetext", "spacer", "span", "strike", 
+  "strong", "style", "sub", "sup", "table", "tbody", "td", "textarea", 
+  "tfoot", "th", "thead", "title", "tr", "tt", "u", "ul", "var", "wbr", "xmp"
 };
 
 nsHTMLTag NS_TagToEnum(const char* aTagName) {
diff --git a/mozilla/parser/htmlparser/src/nsHTMLTags.h b/mozilla/parser/htmlparser/src/nsHTMLTags.h
index a2209558c97..6e5e4195b44 100644
--- a/mozilla/parser/htmlparser/src/nsHTMLTags.h
+++ b/mozilla/parser/htmlparser/src/nsHTMLTags.h
@@ -46,24 +46,25 @@ enum nsHTMLTag {
   eHTMLTag_nobr=66, eHTMLTag_noembed=67, eHTMLTag_noframes=68, 
   eHTMLTag_nolayer=69, eHTMLTag_noscript=70, eHTMLTag_object=71, 
   eHTMLTag_ol=72, eHTMLTag_optgroup=73, eHTMLTag_option=74, eHTMLTag_p=75, 
-  eHTMLTag_param=76, eHTMLTag_plaintext=77, eHTMLTag_pre=78, eHTMLTag_q=79, 
-  eHTMLTag_s=80, eHTMLTag_samp=81, eHTMLTag_script=82, eHTMLTag_select=83, 
-  eHTMLTag_server=84, eHTMLTag_small=85, eHTMLTag_sound=86, 
-  eHTMLTag_spacer=87, eHTMLTag_span=88, eHTMLTag_strike=89, 
-  eHTMLTag_strong=90, eHTMLTag_style=91, eHTMLTag_sub=92, eHTMLTag_sup=93, 
-  eHTMLTag_table=94, eHTMLTag_tbody=95, eHTMLTag_td=96, eHTMLTag_textarea=97, 
-  eHTMLTag_tfoot=98, eHTMLTag_th=99, eHTMLTag_thead=100, eHTMLTag_title=101, 
-  eHTMLTag_tr=102, eHTMLTag_tt=103, eHTMLTag_u=104, eHTMLTag_ul=105, 
-  eHTMLTag_var=106, eHTMLTag_wbr=107, eHTMLTag_xmp=108, 
+  eHTMLTag_param=76, eHTMLTag_parsererror=77, eHTMLTag_plaintext=78, 
+  eHTMLTag_pre=79, eHTMLTag_q=80, eHTMLTag_s=81, eHTMLTag_samp=82, 
+  eHTMLTag_script=83, eHTMLTag_select=84, eHTMLTag_server=85, 
+  eHTMLTag_small=86, eHTMLTag_sound=87, eHTMLTag_sourcetext=88, 
+  eHTMLTag_spacer=89, eHTMLTag_span=90, eHTMLTag_strike=91, 
+  eHTMLTag_strong=92, eHTMLTag_style=93, eHTMLTag_sub=94, eHTMLTag_sup=95, 
+  eHTMLTag_table=96, eHTMLTag_tbody=97, eHTMLTag_td=98, eHTMLTag_textarea=99, 
+  eHTMLTag_tfoot=100, eHTMLTag_th=101, eHTMLTag_thead=102, 
+  eHTMLTag_title=103, eHTMLTag_tr=104, eHTMLTag_tt=105, eHTMLTag_u=106, 
+  eHTMLTag_ul=107, eHTMLTag_var=108, eHTMLTag_wbr=109, eHTMLTag_xmp=110, 
 
   /* The remaining enums are not for tags */
-  eHTMLTag_text=109, eHTMLTag_whitespace=110, eHTMLTag_newline=111, 
-  eHTMLTag_comment=112, eHTMLTag_entity=113, eHTMLTag_userdefined=114, 
-  eHTMLTag_secret_h1style=115, eHTMLTag_secret_h2style=116, 
-  eHTMLTag_secret_h3style=117, eHTMLTag_secret_h4style=118, 
-  eHTMLTag_secret_h5style=119, eHTMLTag_secret_h6style=120
+  eHTMLTag_text=111, eHTMLTag_whitespace=112, eHTMLTag_newline=113, 
+  eHTMLTag_comment=114, eHTMLTag_entity=115, eHTMLTag_userdefined=116, 
+  eHTMLTag_secret_h1style=117, eHTMLTag_secret_h2style=118, 
+  eHTMLTag_secret_h3style=119, eHTMLTag_secret_h4style=120, 
+  eHTMLTag_secret_h5style=121, eHTMLTag_secret_h6style=122
 };
-#define NS_HTML_TAG_MAX 108
+#define NS_HTML_TAG_MAX 110
 
 extern NS_HTMLPARS nsHTMLTag NS_TagToEnum(const char* aTag);
 extern NS_HTMLPARS const char* NS_EnumToTag(nsHTMLTag aEnum);
diff --git a/mozilla/parser/htmlparser/src/nsParserError.h b/mozilla/parser/htmlparser/src/nsParserError.h
index f2cab09e790..7925f0dd623 100644
--- a/mozilla/parser/htmlparser/src/nsParserError.h
+++ b/mozilla/parser/htmlparser/src/nsParserError.h
@@ -35,9 +35,8 @@ typedef struct _nsParserError {
   PRInt32 code;
   PRInt32 lineNumber;
   PRInt32 colNumber;  
-  nsString description;
-  PRInt32 offset;  
-  nsString sourceBuffer;
+  nsString description;  
+  nsString sourceLine;
 } nsParserError;
 
 #endif